The present invention relates generally to step attenuators, and more particularly, to a step attenuator circuit that uses a PIN diode and which is adapted for use in temperature compensation devices employed with monolithic microwave integrated circuits) MMIC) and microwave integrated circuits (MIC).
Previously, one of the ways to provide for temperature compensation microwave amplifiers, such a discrete and MMIC amplifiers, and the like, was achieved by controlling the current through a shunt diode in conjunction with a single thermistor circuit. The attenuation produced by this arrangement was dependent upon the amount of current passing through the diode. Consequently, the amount of attenuation produced by this arrangement was variable, as a function of current, and was not fixed as is achievable by a step attenuator. Tuning the thermistor circuit was necessary to provide a correct attenuation range that was required for a given temperature range. This typically involves time-consuming temperature tests in order to produce a circuit that satisfied requirements.
Consequently, it is an objective of the present invention to provide for an attenuator that provides for fixed attenuation steps. It is a further objective of the present invention to provide for an attenuator for use in temperature compensation devices that reduces testing time and provides for control in achieving compensation over desired temperature ranges.